Electromagnetic brake incorporated in spinning or twisting spindles

ABSTRACT

In a spinning or twisting spindle assembly there is incorporated an electromagnetically operated brake mechanism which is formed of the following basic components: A MAIN MEMBER INCLUDING AN IRON RING FIXEDLY SECURED TO THE STATIONARY SPINDLE SUPPORT HOUSING AND A SOLENOID DISPOSED IN SAID RING; AN INTERMEDIATE ANNULAR MEMBER LINEARLY MOVABLE PARALLEL TO THE SPINDLE AXIS AND INCLUDING TWO ANNULAR, SPACED, COAXIAL FLUX-CONDUCTING ZONES AND AN ANNULAR BRAKE SHOE MEMBER DISPOSED BETWEEN THE TWO ANNULAR FLUX-CONDUCTING ZONES; AN ARMATURE ROTATING WITH THE ROTARY SPINDLE PART AS A UNIT AND BEING FRICTIONALLY ENGAGED BY THE BRAKE SHOE OF THE INTERMEDIATE MEMBER UPON ENERGIZATION OF THE SOLENOID.

T I bmted States Patent 11 1 1111 3,749,955 Fetzer July 31, 1973 [54]ELECTROMAGNETIC BRAKE 2,461,759 211949 Nelson 310/77 ux INCORPORATED INSPINNING OR 1x32; x qt as o TWISTING SPINDLES 3,176,173 3/1965 Straub310 77 Inventor: Gustav Fetzer, Gingen, Germany Zinser-TextilmaschinenGmbl-l, Ebersbach, Germany Filed: Mar. 20, 1972 Appl. No.: 236,076

Assignee:

US. Cl. 310/93, 310/77 Int. Cl. l-l02k 49/00 .Field of Search .L 310/93,29, 92, 34,

References Cited UNITED STATES PATENTS Primary Examiner-R. SkudyAttorney-Edwin E. Greigg linearly movable parallel to the spindle axisand including two annular, spaced, coaxial flux-conducting zones and anannular brake shoe member disposed between the two annularflux-conducting zones; an armature rotating with the rotary spindle partas a unit and being frictionally engaged by the brake shoe of theintermediate member upon energization of the solenoid.

7 Claims, 4 Drawing Figures PAIENIEUJUI. 3 I rm SHEET 2 [IF 2ELECTROMAGNETIC BRAKE INCORPORATED IN SPINNING OR TWISTING SPINDLESBACKGROUND OF THE INVENTION This invention relates to a spinning ortwisting spindle for use in spinning, twisting or draw twisting machinesand is of the type which is provided with a brake mechanism for brakingthe rotary spindle part. The brake mechanism, in turn, is of the typethat has at least one electromagnet containing at least one solenoid andan armature affixed to the rotary part of the spindle. Upon energizationof the electromagnet, a friction face, which is prevented from'rotatingwith the rotary spindle part, is pressed against the armature.

In a known spindle structure of the type outlined above, the brakemechanism includes an electromagnet which, as a whole, is axiallymovable and is supported coaxially with the spindle axis. Uponenergization of the solenoid carried by this known electromagnet, thelatter, in response to the magnetic forces generated between theelectromagnet and its armature, is moved against gravity and is pressedagainst the armature to thus brake the same until it comes to astandstill. This type of brake mechanism has significant advantages withrespect to other known brake assemblies, since it is structurallysimple, it does not have the tendency to rust and has a uniform brakingeffect without the tendency of rattling. Further, this known brakemechanism exerts practically no force on the bearing of the rotaryspindle part during the braking operation.

The aforeoutlined known brake mechanism has, however, severaldisadvantages. Thus, the electromagnet, when energized, strikes thearmature too forcefully, its conductor for the current feed cannot befixedly secured, it is complicated to replace the solenoid and it isdifficult to secure the brake face to the electromagnet in a replaceablemanner.

OBJECT AND SUMMARY OF THE INVENTION It is an object of the invention toprovide an electromagnetically operated improved brake mechanismincorporated in a spindle assembly from which the above-outlineddisadvantages are eliminated.

Briefly stated, according to the invention, with a spinning or twistingspindle of the aforenoted type there is associated a brake mechanismwhich has an electromagnet comprising a main member that carries atleast one solenoid and is held stationary relative to the housing of thespindle bearing. The main member has poles which extend normal to thedirection of motion of a linearly displaceable intermediate member alsoforming part of the electromagnet. The intermediate member has at leasttwo spaced, magnetizable flux-conducting zones and at least one brakingface cooperating with the armature for braking the latter. Thefluxconducting zones of the intermediate member have first poles whichare disposed parallel to and adjacent opposite poles of the main memberwithout clearance or spaced therefrom by a small air gap and secondpoles which are adjacent the armature and extend in the direction ofmotion of the intermediate member. In the de-energized condition of thesolenoid, the intermediate member, either by its own weight or by springmeans (or the combination thereof) is maintained out of engagement withthe armature, whereas during the energized condition of the solenoid, itis pressed into contact with the magnet armature by virtue of themagnetic attraction forces generated between its said second poles andthe armature.

The invention will be better understood, as well as further objects andadvantages become more apparent, from the ensuing detailed specificationof several exemplary embodiments taken in conjunction with the drawing.

BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE FIRST EMBODIMENTTurning now to FIG. 1, the spindleassembly shown therein in afragmentary manner includes a spindle support housing 11 which issecured in a ring rail 10 and which accommodates bearing means forsupporting the rotary spindle part 14. The latter includes a spindleshaft 15 and a whorl l6 fixedly attached thereto. The lower flange 17 ofthe whorl 16 serves as an armature of an electromagnetic brake assemblygenerally indicated at 19 and built according to the invention. Allcomponents of the brake assembly which serve for conducting the magneticfiux are rotationally symmetrical with respect to the spindle axis andare arranged coaxially therewith. The brake assembly 19, in addition tothe armature 17, has a multipart electromagnet generally indicated at 20which includes a ring 21 made of soft iron and fixedly attached to thespindle support housing 11, a solenoid 23 disposed fixedly in arotationally symmetrical channel 22 of the ring 21 and an intermediateannular member 24 received in the channel 22 above the solenoid 23. Theintermediate member 24 is guided linearly in the direction of thespindle axis by means of a plurality of radially outwardly extendingmembers in the form of pins 25 (only oneshown) which-are affixed to theouter wall of the intermediate member 24 and which slide with a smallclearance in axially parallel slots provided in the ring 21.

The cooperating sliding faces of the ring 21 and the intermediate member24 are of cylindrical configuration. The ring 21 and the solenoid 23constitute the main member 28 of the electromagnet 20 and are immobilewith respect to the spindle support housing 11.

The intermediate member 24 is formed as an annulus of rectangular crosssection which has two coaxial annular flux-conducting zones 26 and 27made of soft iron and arranged in a radial-distance from one another.The radial spacing between the zones 26 and 27 is ensured by aninterposed connecting annular brake shoe member 29 which is made of anon-magnetizable, for example, synthetic material. The upper planarradial face of the brake shoe member 29 serves as a braking face whichcooperates with the lower planar radial 3 face of the armature 17 forbraking the rotary spindle part 14.

OPERATION OF THE FIRST EMBODIMENT In FIG. 1 the intermediate member 24is shown in its lowest position'which it assumes by virtue of its ownweight when the solenoid 23 is in a-de-energized condition. In thisposition the upper radial face of the intermediate member 24 is at asmall distance below the lower radial face of the armature 17. Thislowest position of the intermediate member 24 is determined by anengagement of the linear guiding pins 25 with the base of theguide'slots provided in the iron ring 21. When the solenoid 23 isenergized, a magnetic field in generated which is illustrated by amagnetic force line 30'. In this manner, at the vertical cylindricalinner wall faces of the iron ring 21 poles of opposite polarity areformed. Adjacent and parallel to these poles there extend first poles ofthe intermediate member 24. These first poles are formed on the convex,external cylinder faces of the flux-conducting zones 26, 27. Since themagnetic field is closed in an annular manner, at the planar annularradial faces of the flux-conducting zones 26, 27, second poles areformed which cooperate with poles that are formed on the adjacent radialface of the armature 17. The magnetic attracting forces generated inthis manner between the armature l7 and the intermediate member 24 pullthe latter vertically upwardly until the braking face of theintermediate member 24 is firmly pressed against the armaturel7 and thusexerts a braking force thereon.

It is apparent that between the upper radial faces of the iron ring 21and the armature 17 secondary magnetic circuits may be formed. Since,however, the distance between these radial faces and the armature 17 isrelatively large and remains unchanged, such scattered fluxes arerendered ineffective at the latest when the intermediate member 24arrives into engagement with the armature 17, since then the magneticflux is closed substantially only through the intermediate member 24 andthe armature l7. Immediately subsequent to the energization of theelectromagnet, however, an appreciable part ofthe magnetic flux may forma circuit directly by extending from the ring2l to the armature 17 andback into the ring 21. In this manner, the acceleration imparted on theintermediate member 24 is decreased, resulting in a dampened impact ofthe intermediate member 24 on the armature 17. As soon as theintermediate member 24 is in engagement with the armature 17, theaforediscussed scattered flux becomes small and practically does notaffect the magnitude of the braking moment to be achieved.

DESCRIPTION OF THE SECOND EMBODIMENT Turning now to FIG. 2, the annularintermediate member 30 of the electromagnet 31 forming part of the brakeassembly has an approximately U-shaped cross section. Its mid portion isformed by a straddling annular disc constituting a brake shoe 32 made ofa non-magnetizable material. The two flux-conducting zones 33, 34 of theintermediate member 30 are formed as cylindrical rings made of softiron. The outer cylindrical ring 33 has, at several locations of itscircumference, radially inwardly bent extension members in the form oftabs which extend into axially parallel slots of an iron ring 35 of themain member 37. The latter is held fixedly between the spindle rail anda collar 36 of the spindle support housing 11. By virtue of thecooperation between the aforenoted tabs and axially parallel slots, theintermediate member 30 is guided during its displacement linearly and inan axial direction.

The outer iron ring 33 of the intermediate member 30 surrounds the ironring 35 of the main member 37 of the electromagnet with a smallclearance, whereas the inner ring 34 of the intermediate member 30extends, with an air gap, adjacent that cylindrical face of the ironring 35 that is closest to the spindle axis.

In the lowest position assumed by its own weight during the de-energizedcondition of the solenoid shown in FIG. 2, the intermediate member 30engages with its brake shoe 32 the upper radial face of the iron ring 35of the main member 37 forming part of the electromagnet 31. When theelectromagnet is energized, the intermediate member 30 is pulledupwardly by virtue of the magnetic attracting forces generated betweenits second poles 38, 39 and the armature 17, in principle in the samemanner as described in connection with the embodiment illustrated inFIG. 1. As a result, the brake shoe 32 is firmly pressed against thearmature 17 for braking the latter.

The whorl 16 of the rotary spindle part 14 is again, as it is in theembodiment according to FIG. 3, fixedly secured to the spindle shaft 15and its lower flange forms the armature 17 of the brake assembly.

DESCRIPTION OF THE THIRD EMBODIMENT In the embodiment according to FIG.3, the main member 40 of the electromagnet 41 is designed similarly tothat shown in FIG. 1, with the difference that the solenoid 42 takes upmore space in the channel 43 of the iron ring 44 which forms part of themain component 40 and which is fixedly secured to the spindle sup porthousing 11.

The annular intermediate member 45 of the electromagnet 41 is, here too,rotationally symmetrically arranged and has a rectangular cross section.One of its flux-conducting zones 46 is formed as a cylindrical ringwhich surrounds the outer cylindrical face of the iron ring 44 of themain member 40 and has on itscircumference a plurality of axiallyparallel spaced slots. Into each slot there projects a radial extensionmember in the form of a pin 47 which is fixedly secured to the mainmember 40 and which serves for the linear guidance of the intermediatemember 45 for its movement parallel to the spindle axis and relative tothe ring 44. The brake shoe 48 of the intermediate member 45 is designedas a planar annular disc; it connects the outer iron ring 46 with aninner iron ring 49. The latter is adjacent and in sliding relationshipwith the cylindrical side wall of the channel 43 formed in the iron ring44 of the main component 40 which has the smaller radius. The operationof the brake assembly according to FIG. 3 is, in principle, identical tothose shown in FIGS. 1 and 2 and needs therefore no further elaboration.

DESCRIPTION OF THE FOURTH EMBODIMENT In the embodiment according to FIG.4 there is illustrated a spindle, the whorl 50 of which is rotatablysupported in a known manner on the rotatable spindle part 14 by meansofroller bearings 51. The purpose of this arrangement is to make possiblean uncoupling of the whorl 50 from the rotary spindle part 14 duringbraking so that the whorl 50 may be continuously rotated part 14'. Forthis purpose there is provided a clutch member 53 which also serves asthe armature of the electromagnetic brake assembly 52 and which isaxially guided on a carrier sleeve 54 of the rotary spindle part 14'.The clutch member 53 is spring biased by means of compression springs 56one inserted on each of a plurality of pins 55 and is thus continuouslyurged in a direction away from the electromagnet 57. In this manner aclutch face 58 mounted on the clutch member 53 is, in the normaloperating position, pressed into engagement with a planar lower radialface of the whorl 50 and thus a firm connection is effected between thewhorl 50 and the rotary spindle part 14.

The disconnection of the clutch'member 53 from the rotary spindle part14' is effected by virtue of the operation of the electromagnet 57.Simultaneously, the clutch member 53 which at all times rotates with therotary spindle part 14 as a unit, is braked, thus also effecting therotary spindle part 14.

The embodiment illustrated in FIG. 4 is thus a combined,electromagnetically operated brake-and-clutch assembly, the structure ofwhich will now be described.

The electromagnet 57 has a mainmember 59 which is fixedly secured to thespindle support housing 11 and which is formed of an iron ring 60 ofU-shaped cross section and a solenoid 62 disposed in the annular channel61 of the ring 60. In the channel 61 there is disposed, in a manneridentical in principle to the embodiment according to FIG. 1, anintermediate member 63 of the electromagnet 57. The intermediate member63 is axially movably supported and is linearly guided by means ofradially outwardly extending extension members in the form of screws 67carried on the periphery of the intermediate member 63 and extendinginto axially parallel spaced slotsprovidedin the outer circumferentialwall of the iron ring 60.

Inner and outer coaxial iron rings 64 and 65 of the intermediate member63 form flux conducting zones and are radially spaced and connected withone another by means of a ring 66 made of an insulating material. Thering 66 is embedded between the two rings 64, 65 and has an upper radialface which serves as a frictional brake face.

In FIG. 4 the intermediate member 63 is shown in its uppermost positionwhich is determined by the engagement of the screws 67 with the upperedge of the slots provided in the iron ring 60. FIG. 4 depicts amomentary position of the brake assembly 52 which it assumes shortlyafter the energization of the solenoid 62. In this position theintermediate member 63 has been lifted off its lower position and movedinto its shown upper position by virtue of the magnetic attractionforces generated between the intermediate member 63 and the clutchmember 53 which also serves as the magnet armature. As soon as theintermediate member 63 has reached the last-named upper position, themagnetic attracting force then prevailing between the intermediatemember 63 and the armature or clutch member 53 causes the latter to movedownwardly until it engages the brake'face of the intermediate member63. It is seen that the downward movement of the clutch member 53 meansthe uncoupling of the whorl 50 from the rotary spindle part 14'. Sinceas it wasmentioned earlier the clutch member 53 always remainsrotationally coupled to the rotary spindle part 14', a brak- 6 ingengagement between the lower radial face of the clutch member 53 and theupper radial face of the nonrotatable intermediate member 63 alsoefi'ects a braking of the rotary spindle part 14.

The axial displaceability of the intermediate member 63 is advantageousin that at the moment of energization of the electromagnet, the magneticattracting forces generated between the intermediate member 63 g and theclutch member 53 have to be only aslarge as is necessary to lift theintermediate member 63 into its shown uppermost position against its ownweight. Consequently, the initial air gap between the intermediatemember 63 and the clutch member 53 may be relatively large. When theintermediate member 63 has reached its uppermost position, theaforenamed air gap has already decreased substantially and thus themagnetic attracting forces between the intermediate member 63 and theclutch member 53 have increased to such an extent that they are nowcapable to pull the clutch' member 53 against the force of the biasingsprings 56 downwardly to press it against the intermediate member 63.

By providing the possibility to design a relatively large air gapbetween the intermediate member 63 and the clutch member 53, theoperational safety of the brake assembly is increased and the cost ofmanufacturing lowered. This advantage is, of course, also present in theembodiments according to FIGS. 1-3 because there, too, due to the smallweight of the intermediate member, large air gaps may be providedbetween the intermediate member and the armature, because immediatelysubsequent to the energization of the electromagnet only a lifting forcehas to be exerted on the relatively light intermediate member toovercome its weight.

SUMMARY OF THE ADVANTAGES AND EXAMPLES OF FURTHER MODIFICATIONS As seen,the main member 28; 37; 59 of the electromagnet 20; 31; 41; 57 is alwaysstationary and thus no drawbacks are introduced if it is designed as arelatively heavy component.

During the braking operation it is only the intermediate member 24; 30;63 which is exposed to wear. If a new brake face is required, the entireinexpensive intermediate member is simply replaced.

The structure according to the invention further permits anuncomplicated replacement of the solenoid. The latter becomes accessibleafter lifting off the intermediate member.

Since the solenoid and its support always remain stationary, theelectric conductor leading to the solenoid may be secured in a fixed,immobilized manner and is thus well protected from damage.

During operation of the brake mechanism, the solenoid is not exposed toany impact as it is the case in prior art devices where the solenoid andits support,

too, move against the armature. Also, the impact with which theintermediate member strikes the armature upon energization of thesolenoid is relatively small due to the relatively small mass of theintermediate member.

The load on the bearings of the rotary spindle part due to braking iseven smaller than in spindlebrakes of known structure.

It is essential for the operationof the intermediate member that itsdirection of motion is approximately normal to the magnetic fieldgenerated between the intermediate member and the main member, becausein this manner it is ensured that despite the presence of this magneticfield the intermediate member is readily displaceable in an axialdirection. In contradistinction, the magnetic field generated betweenthe intermediate member and the armature 17 is substantially parallel tothe direction of motion of the intermediate member. Consequently,between these two components significant magnetic attracting forcesappear which pull the intermediate member to the armature.

In all four exemplary embodiments described hereinabove, the structurecontained but a single electromagnet. It is to be understood thatinstead of a sole electromagnet two or more electromagnets of identicalor similar structure may be used. In such a case each electromagnet isbuilt according to the invention. The use of a plurality ofelectromagnets is expedient, for example, when the brake faces of thebrake mechanism extend parallel to the spindle axis, so that theintermediate member moves radially with respect to the spindle axis. Insuch an arrangement it is expedient to use two or more electromagnetsdisposed equally spaced in a circular array.

That which is claimed is: I

I. In an electromagnetic brake assembly incorporated in spinning ortwisting spindles having a rotary spindle part to be braked and aspindle housing for supporting said rotary spindle part, said brakeassembly having an electromagnet including at least one solenoid, anarmature rotating with said rotary spindle part as a unit and a brakeshoe adapted to be pressed against said armature upon energization ofsaid solenoid to brake said rotary spindle part, the improvement in saidelectromagnet comprising A. a main member having at least one solenoidand being held immobile with respect to said spindle housing, said mainmember having poles thereon,

B. an intermediate member linearly movable with respect to said mainmember in a direction parallel to the course of said poles thereon, saidintermediate member having l. at least two spaced rings disposedcoaxially with respect to one another and the spindle axis, said spacedrings constituting two flux-conducting zones which have first polesextending parallel to and adjacent opposite poles on said main memberand second poles. disposed adjacent said armature in the direction ofmotion of said intermediate member,

2. a non-magnetizable ring extending between said two spaced rings formagnetically separating and mechanically connecting the same, saidnon-magnetizable ring carrying at least one brake face cooperating withsaid armature,

C. means maintaining said intermediate member out of contact with saidarmature during the deenergized condition of said solenoid, said meansbeing overcome by the force of the magnetic field generated between saidsecond poles of said intermediate member and said armature during theenergized condition of said solenoid for pressing said intermediatemember with said brake face against said armature, and

D. means for linearly guiding said intermediate member parallel to thespindle axis.

2. In an electromagnetic brake assembly incorporated in spinning ortwisting spindles having a rotary spindle part to be braked and aspindle housing for supporting said rotary spindle part, said brakeassembly having an electromagnet including at least one solenoid, anarmature rotating with said rotary spindle part as a unit and a brakeshoe adapted to be pressed against said armature upon energization ofsaid solenoid to brake said rotary spindle part, the improvement in saidelectromagnet comprising A. a main member having at least one solenoidand being held immobile with respect to said spindle housing, said mainmember having poles thereon,

B. an intermediate member linearly movable with respect to said mainmember in a direction parallel to the course of said poles thereon, saidintermediate member havingl. at least two flux-conducting zones spacedfrom one another, said flux-conducting zones having first poles formedas cylindrical surfaces which extend parallel to and adjacent oppositepoles on said main member and second poles formed as planar annularsurfaces extending normal to said cylindrical surfaces and disposedadjacent said armature in the direction of motion of said intermediatemember,

2. at least one brake face cooperating with said armature, and v a C.means maintaining said intermediate member out of contact with saidarmature during the deenergized condition of said solenoid, said meansbeing overcome by the force of the magnetic field generated between saidsecond poles of said intermediate member and said armature during theenergized condition of said solenoid for pressing said intermediatemember with said brake face against said armature.

3. In an electromagnetic brake assembly incorpo' rated in spinning ortwisting spindles having a rotary spindle part to be braked and aspindle housing for supporting said rotary spindle part, said brakeassembly having an electromagnet including at least one solenoid, anarmature rotating with said rotary spindle part as a unit and a brakeshoe adapted to be pressed against said armature upon energization ofsaid solenoid to brake said rotary spindle part, the improvement in saidelectromagnet comprising A. a main member having poles thereon, twospaced external faces and at least one solenoid, said main member beingheld immobile with respect to said spindle housing, I B. an intermediatemember linearly movable with respect to said main member in a directionparallel to the course of said poles thereon, said intermediate rnemberhaving '7 v 1 I l. at least two flux-conducting zones spaced from oneanother and each extending adjacent a different one of said externalfaces, said fluxconducting zones having first poles extending parallelto and'adjacent opposite poles on said main member and second polesdisposed adjacent said-armature in the direction of motion of saidintermediate member, 2. at least one brake face cooperating with saidarmature, and v V C. means maintaining said intermediate member out ofcontact with said armature during the deenergized condition of saidsolenoid, said means being overcome by the force of the magnetic fieldgenerated between said second poles of said intermediate member and saidarmature during the energized condition of said solenoid for pressingsaid intermediate member with said brake face against said armature.

4. In an electromagnetic brake assembly incorporated in spinning ortwisting spindles having a rotary spindle part to be braked and aspindle housing for supporting said rotary spindle part, said brakeassembly having an electromagnet including at least one solenoid, anarmature rotating with said rotary spindle part as a unit and a brakeshoe adapted to be pressed against said armature upon energization ofsaid solenoid to brake said rotary spindle part, the improvement in saidelectromagnet comprising A. a main member having poles thereon, at leastone solenoid, an external lateral wall face, a frontal face with arecess provided therein and an inner lateral wall face bounding saidrecess, said main member being held immobile with respect to saidspindle housing,

B. an intermediate member linearly movable with respect to said mainmember in a direction parallel to the course of said poles thereon, saidintermedi ate member having l. at least two flux-conducting zones spacedfrom one another, with one flux-conducting zone extending adjacent saidexternal lateral wall face and the other flux-conducting zone extendingad jacent said inner lateral wall face, said fluxconducting zones havingfirst poles extending parallel to and adjacent opposite poles on saidmain member and second poles disposed adjacent said armature in thedirection of motion of said intermediate member,

2. at least one brake face cooperating with said armature, and I C.means maintaining said intermediate member out of contact with saidarmature during the deenergized condition of said solenoid, said meansbeing overcome by the force of the magnetic field generated between saidsecond poles of said intermediate member and said armature during theenergized condition of said solenoid for pressing said intermediatemember with said brake face against said armature.

5. In an electromagnetic brake assembly incorporated in spinning ortwisting spindles having a rotary spindle part to be braked anda spindlehousing for supporting said rotary spindle part, said brake assemblyhaving an electromagnet including atleast one solenoid, an armaturerotating with said rotary spindle part as a unit and a brake shoeadapted to be pressed against said armature upon energization of saidsolenoid to D. an intermediate member linearly movable with respect tosaid main member in a direction parallel to the course of said polesthereon, said intermediate member having I. at least two flux-conductingzones spaced-from one another, said flux-conducting zones having firstpoles extending parallel to and adjacent opposite poles on said mainmember and second poles disposed adjacent said armature in the directionof motion of said intermediate member,

2. at least one brake face cooperating with said armature,

E. abutment means limiting the displacement of said intermediate membertowards said armature in response to the energization of said solenoid,said abutment means arresting said intermediate member in itsdisplacement towards said armature in a position spaced from theposition of rest of said armature,

F. means maintaining said intermediate member out of contact with saidarmature during the deenergized condition of said solenoid, said meansbeing overcome by the force of the magnetic field generated between saidsecond poles of said intermediate member and said armature during theenergized condition of said solenoid for pressing said intermediatemember against said abutment means, and

G. means for axially moving said armature to engage said intermediatemember in its position arrested by said abutment means.

6. An improvement as defined in claim 5, wherein said spindle includes awhorl rotatably supported with respect to said rotary spindle part, saidarmature being formed as a clutch member rotationally coupling saidwhorl to said rotary spindle part in said position of rest, said clutchmember uncoupling said whorl and said rotary spindle part upon axialmovement of said clutch member towards said intermediate member againstthe force of said spring means in response to the energization of saidsolenoid.

7. In an electromagnetic brake assembly incorporated in spinning ortwisting spindles having a rotary spindle part to be braked and aspindle housing for supporting said rotary spindle part, said brakeassembly having an electromagnet including at least one solenoid, anarmature rotating with said rotary spindle part as a unit and a brakeshoe adapted to be pressed against said armature upon energization ofsaid solenoid to brake said rotary spindle part, the improvement in saidelectromagnet comprising A. a main member having at least one solenoidand being held immobile with respect to said spindle housing, said mainmember having poles thereon,

B. an intermediate member linearly movable with re spect to said mainmember in a direction parallel to the course of said poles thereon, saidintermediate member having I. at least two flux-conducting zones spacedfrom one another, said flux-conducting zones having first polesextending parallel to and adjacent opposite poles on said main memberand second poles disposed adjacent said armature in the direction ofmotion of said intermediate member, 2. at least one brake facecooperating with said armature,

said armature, and I D. cooperating means in the form of an extensionmember mounted on said intermediate member and a slot formed in saidmain member, said extension member being insertable within said slot tolinearly guide said intermediate member on and with respect to said mainmember.

8 t I I I!

1. In an electromagnetic brake assembly incorporated in spinning ortwisting spindles having a rotary spindle part to be braked and aspindle housing for supporting said rotary spindle part, said brakeassembly having an electromagnet including at least one solenoid, anarmature rotating with said rotary spindle part as a unit and a brakeshoe adapted to be pressed against said armature upon energization ofsaid solenoid to brake said rotary spindle part, the improvement in saidelectromagnet comprising A. a main member having at least one solenoidand being held immobile with respect to said spindle housing, said mainmember having poles thereon, B. an intermediate member linearly movablewith respect to said main member in a direction parallel to the courseof said poles thereon, said intermediate member having
 1. at least twospaced rings disposed coaxially with respect to one another and thespindle axis, said spaced rings constituting two flux-conducting zoneswhich have first poles extending parallel to and adjacent opposite poleson said main member and second poles disposed adjacent said armature inthe direction of motion of said intermediate member,
 2. anon-magnetizable ring extending between said two spaced rings formagnetically separating and mechanically connecting the same, saidnon-magnetizable ring carrying at least one brake face cooperating withsaid armature, C. means maintaining said intermediate member out ofcontact with said armature during the de-energized condition of saidsolenoid, said means being overcome by the force of the magnetic fieldgenerated between said second poles of said intermediate member and saidarmature during the energized condition of said solenoid for pressingsaid intermediate member with said brake face against said armature, andD. means for linearly guiding said intermediate member parallel to thespindle axis.
 2. at least one brake face cooperating with said armature,C. means maintaining said intermediate member out of contact with saidarmature during the de-energized condition of said solenoid, said meansbeing overcome by the force of the magnetic field generated between saidsecond poles of said intermediate member and said armature during theenergized condition of said solenoid for pressing said intermediatemember with said brake face against said armature, and D. cooperatingmeans in the form of an extension member mounted on said intermediatemember and a slot formed in said main member, said extension memberbeing insertable within said slot to linearly guide said intermediatemember on and with respect to said main member.
 2. at least one brakeface cooperating with said armature, E. abutment means limiting thedisplacement of said intermediate member towards said armature inresponse to the energization of said solenoid, said abutment meansarresting said intermediate member in its displacement towards saidarmature in a position spaced from the position of rest of saidarmature, F. means maintaining said intermediate member out of contactwith said armature during the de-energized condition of said solenoid,said means being overcome by the force of the magnetic field generatedbetween said second poles of said intermediate member and said armatureduring the energized condition of said solenoid for pressing saidintermediate member against said abutment means, and G. means foraxially movinG said armature to engage said intermediate member in itsposition arrested by said abutment means.
 2. a non-magnetizable ringextending between said two spaced rings for magnetically separating andmechanically connecting the same, said non-magnetizable ring carrying atleast one brake face cooperating with said armature, C. meansmaintaining said intermediate member out of contact with said armatureduring the de-energized condition of said solenoid, said means beingovercome by the force of the magnetic field generated between saidsecond poles of said intermediate member and said armature during theenergized condition of said solenoid for pressing said intermediatemember with said brake face against said armature, and D. means forlinearly guiding said intermediate member parallel to the spindle axis.2. In an electromagnetic brake assembly incorporated in spinning ortwisting spindles having a rotary spindle part to be braked and aspindle housing for supporting said rotary spindle part, said brakeassembly having an electromagnet including at least one solenoid, anarmature rotating with said rotary spindle part as a unit and a brakeshoe adapted to be pressed against said armature upon energization ofsaid solenoid to brake said rotary spindle part, the improvement in saidelectromagnet comprising A. a main member having at least one solenoidand being held immobile with respect to said spindle housing, said mainmember having poles thereon, B. an intermediate member linearly movablewith respect to said main member in a direction parallel to the courseof said poles thereon, said intermediate member having
 2. at least onebrake face cooperating with said armature, and C. means maintaining saidintermediate member out of contact with said armature during thede-energized condition of said solenoid, said means being overcome bythe force of the magnetic field generated between said second poles ofsaid intermediate member and said armature during the energizedcondition of said solenoid for pressing said intermediate member withsaid brake face against said armature.
 2. at least one brake facecooperating with said armature, and C. means maintaining saidintermediate member out of contact with said armature during thede-energized condition of said solenoid, said means being overcome bythe force of the magnetic field generated between said second poles ofsaid intermediate member and said armature during the energizedcondition of said solenoid for pressing said intermediate member withsaid brake face against said armature.
 2. at least one brake facecooperating with said armature, and C. means maintaining saidintermediate member out of contact with said armature during thede-energized condition of said solenoid, said means being overcome bythe force of the magnetic field generated between said second poles ofsaid intermediate member and said armature during the energizedcondition of said solenoid for pressing said intermediate member withsaid brake face against said armature.
 3. In an electromagnetic brakeassembly incorporated in spinning or twisting spindles having a rotaryspindle part to be braked and a spindle housing for supporting saidrotary spindle part, said brake assembly having an electromagnetincluding at least one solenoid, an armature rotating with said rotaryspindle part as a unit and a brake shoe adapted to be pressed againstsaid armature upon energization of said solenoid to brake said rotaryspindle part, the improvement in said electromagnet comprising A. a mainmember having poles thereon, two spaced external faces and at least onesolenoid, said main member being held immobile with respect to saidspindle housing, B. an intermediate member linearly movable with respectto said main member in a direction parallel to the course of said polesthereon, said intermediate member having
 4. In an electroMagnetic brakeassembly incorporated in spinning or twisting spindles having a rotaryspindle part to be braked and a spindle housing for supporting saidrotary spindle part, said brake assembly having an electromagnetincluding at least one solenoid, an armature rotating with said rotaryspindle part as a unit and a brake shoe adapted to be pressed againstsaid armature upon energization of said solenoid to brake said rotaryspindle part, the improvement in said electromagnet comprising A. a mainmember having poles thereon, at least one solenoid, an external lateralwall face, a frontal face with a recess provided therein and an innerlateral wall face bounding said recess, said main member being heldimmobile with respect to said spindle housing, B. an intermediate memberlinearly movable with respect to said main member in a directionparallel to the course of said poles thereon, said intermediate memberhaving
 5. In an electromagnetic brake assembly incorporated in spinningor twisting spindles having a rotary spindle part to be braked and aspindle housing for supporting said rotary spindle part, said brakeassembly having an electromagnet including at least one solenoid, anarmature rotating with said rotary spindle part as a unit and a brakeshoe adapted to be pressed against said armature upon energization ofsaid solenoid to brake said rotary spindle part, the improvement in saidelectromagnet comprising A. means for axially movably securing saidarmature to said rotary spindle part, B. spring means for urging saidaxially movable armature away from said electromagnet into a position ofrest, C. a main member having at least one solenoid and being heldimmobile with respect to said spindle housing, said main member havingpoles thereon, D. an intermediate member linearly movable with respectto said main member in a direction parallel to the course of said polesthereon, said intermediate member having
 6. An improvement as defined inclaim 5, wherein said spindle includes a whorl rotatably supported withrespect to said rotary spindle part, said armature being formed as aclutch member rotationally coupling said whorl to said rotary spindlepart in said position of rest, said clutch member uncoupling said whorland said rotary spindle part upon axial movement of said clutch membertowards said intermediate member against the force of said spring meansin response to the energization of said solenoid.
 7. In anelectromagnetic brake assembly incorporated in spinning or twistingspindles having a rotary spindle part to be braked and a spindle housingfor supporting said rotary spindle part, said brake assembly having anelectromagnet including at least one solenoid, an armature rotating withsaid rotary spindle part as a unit and a brake shoe adapted to bepressed against said armature upon energization of said solenoid tobrake said rotary spindle part, the improvement in said electromagnetcomprising A. a main member having at least one solenoid and being heldimmobile with respect to said spindle housing, said main member havingpoles thereon, B. an intermediate member linearly movable with respectto said main member in a direction parallel to the course of said polesthereon, said intermediate member having